Conventional flatbed trailers have a frame generally consisting of two flanged beams longitudinally spaced apart and connected to one another by a plurality of transverse beams or cross sills welded to the longitudinal beams. The frame provides a strong, rigid structure to which the floor or bed, landing gear, kingpin, wheels and suspension system are mounted. The frames for flatbed trailers are generally constructed from steel or aluminum beams. Trailers having an aluminum frame are more expensive than those having a steel frame, but are often preferred by those in the trucking business because of their lightweight. State regulations typically limit the total weight of the truck including the load, the trailer, and the tractor. The typical minimum weight for a flatbed trailer having a steel frame is about 10,000 pounds (about 4500 kg), whereas a trailer with an aluminum frame has a typical minimum weight of about 8,500 pounds (about 3900 kg). Either type of flatbed trailer is generally designed to handle loads in excess of the legal weight limits. Therefore, a trucker can haul at least about 1500 pounds (about 700 kg) more with a trailer having an aluminum frame than with a trailer having a steel frame. The resulting savings in wear and tear, labor, and fuel, can pay for the higher initial cost of an aluminum frame many times over during the typical life of a trailer.
For efficient trucking operations, wherein the total truck weight, including the trailer, load and tractor, are at the maximum legal limit, substantial cost savings are possible for even relatively modest reductions in trailer weight. Therefore, any significant reduction in trailer weight would be of great value to the trucking industry.